Messages in this thread | | | From | Alistair Francis <> | Date | Wed, 3 Jul 2019 15:15:13 -0700 | Subject | Re: [PATCH 2/2] riscv/include/uapi: Define a custom __SIGINFO struct for RV32 |
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On Wed, Jul 3, 2019 at 12:47 PM Arnd Bergmann <arnd@arndb.de> wrote: > > On Wed, Jul 3, 2019 at 8:45 PM Alistair Francis <alistair23@gmail.com> wrote: > > > > On Wed, Jul 3, 2019 at 1:41 AM Arnd Bergmann <arnd@arndb.de> wrote: > > > > > > On Wed, Jul 3, 2019 at 2:21 AM Alistair Francis > > > <alistair.francis@wdc.com> wrote: > > > > > > > > The glibc implementation of siginfo_t results in an allignment of 8 bytes > > > > for the union _sifields on RV32. The kernel has an allignment of 4 bytes > > > > for the _sifields union. This results in information being lost when > > > > glibc parses the siginfo_t struct. > > > > > > I think the problem is that you incorrectly defined clock_t to 64-bit, > > > while it is 32 bit in the kernel. You should fix the clock_t definition > > > instead, it would otherwise cause additional problems. > > > > That is the problem. I assume we want to change the kernel to use a > > 64-bit clock_t. > > Certainly not! > > Doing so would likely involve deprecating all system calls that > take a clock_t (anything passing a struct siginfo or struct tms) and > replacements based on clock64_t.
Ah, that's really easy to fix then.
> > > What I don't understand though is how that impacted this struct, it > > doesn't use clock_t at all, everything in the struct is an int or > > void*. > > si_utime/si_stime in siginfo are clock_t.
But they are further down the struct. I just assumed that GCC would align those as required, I guess it aligns the start of the struct to match some 64-bit members which seems strange.
Alistair
> > Arnd
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